Electric valve circuit



June 17, 1941 R. TRC'JGER 2,246,150

ELECTRIC VALVE CIRCUIT Original Filed June 2, 1937 PR/HE IZOVER 4 Figl.I

Inventor": Richard Trdger,

His Attorney.

Patented June 17, 1941 ELECTRIC VALVE CIRCUIT Richard Triiger,Berlin-Zehlendorf-Mitte, Germany, assignor to General Electric Company,a corporation of New York Original application June 2, 1937, Serial No.

146,096. Divided and this application April 22, 1939, Serial No.269,403. In Germany June 11,

Claims.

My invention relates to electric valve control systems and moreparticularly to control circuits for electric valve apparatus.

This application is a division of my copending application Serial No.146,096, entitled Reguthe assignee of the present application.

for electric valve means.

tric valve regulating apparatus.

machine.

machine to maintain the voltage thereof within narrowly defined limitsunder varying load conditions. The stabilizing circuit includes asaturable transformer for impressing on the con- The Fig. 1 of thedrawing dia- The self-excited To supply direct current to the field 5trol member an alternating voltage variable in lating system, filed June2, 1937 and assigned to phase with respect to the anode-cathode voltage,

and also includes an impedance element for im- In electric valve controland regulating syspressing on the control member a negative unitems,such as control and regulating systems for directional biasing potentialWhich also assists dynamo-electric machines, it is frequently imin thecontrol of the electric valve means. portant to provide means forstabilizing the regstabilizing circuit also includes a transformer andulating action of the controlling system to prea unidirectionalconducting device which enervent wide ranges or variations in theelectrical gizes the impedance element and controls the quantity oroperating condition to be maintained. saturable transformer to controlthe conductivity More specifically, in order to utilize th full adof theelectric valve means in accordance with vantages incident to the use ofregulating systhe voltage impressed thereacross. tems entirelyelectrical in nature and operation, a better understanding of yinvention, it is important to provide stabilizing means to reference maybe had to the followin es pmaintain the electrical condition to beregulated tio taken in C ct With e accompanying within predeterminednarrowly defined limits. drawi and its scope W he P d Out n theFurthermore, it has been found that these stappende Cla s. bilizing oranti-hunting arrangements must be r m i l y r p n s n embodiment of ycapable of responding Within very short interinvention disclosed andClaimed n y above Vals of time to modify the effect of the regulatingidentified p in pplica i n, and Fi 2 diaelements of the system whichtend to compenr mm tically h ws my inv n s pp i o sate for rapidlyvarying load conditions. the arrangement of It is an object of myinvention to provide a Referring to 1 Of the eeeempenying drew-- new andimproved electric valve circuit. i there iS diagrammatically Wn an eei'ta- It is another object of my invention to provide tiell System & yo-electr c machine I of a new and improved control or excitation systemthe Synchronous ype aving an armature winding 2 and a field winding 3.Although not limited It is afurther object of my invention to providethereto, I have Chosen to represent y ve a new and improved stabilizingsystem for election, claimed in the above identified pp as applied to adynamo-electric machine of the In accordance with the illustratedembodiment Synchronous yp which is oper in s a eneraof my invention, Iprovide an electric valve regutor driven y a S b e prime mover 4. Anallating system for controlling the excitation of a temeting CurrentCircuit 5 ec d to the field circuit of a dynamo-electric machine of thearmature windings 2 0f machine I. ynchronous type in accordance t Mede-An excitation system for the dynamo-electric termined electricalcondition, such as the voltage 40 machine I includes a Self-excited YOnOUS a1- or t current of t armature winding of t ternating currentgenerator 6 having an arma- Th field Winding is variably enerturewinding 1 provided with a neutral connecgized by means of electric valveapparatus of the tion 3 and a field Winding controlled type having acontrol member for generator 6 y be arr d o e r v n y he controlling thecurrent conducted thereby. The prime mover 4 and the field Structure ofe eracontrol or excitation circuit is responsive to the 1301 5 y be ou don the same shaft with armature voltage of the synchronous machine efield Structure Of the y ectric maand comprises apparatus for varyingthe phase Ohms impressed on the control member in response to Winding 9of generator 6 and t0 u p y direct the armature voltage, and alsoincludes means current t0 the d W nding 3 of dy amo-electric forsimultaneously varying a unidirectional biasachine I employ an electricvalve means It] ing potential impressed on the control member. havinganodes II and I2 and a cathode l3. The The latter voltage acts as astabilizing voltage to electric valve means In may be of the typeemprevent hunting and hence controls the energizaploy-ing an ionizablemedium, such as a gas or a tion of a field Winding of thedynamo-electric vapor, and may include an auxiliary anode l2.

Anodes ll and I2 are connected to the terminals of armature winding 1through conductors I l and I and the auxiliary anode i2 is connected tothe neutral connection 8 of armature winding '1 through a conductor I6and a current limiting resistance ll. Cathode I3 is connected to thefield circuits for dynamo-electric machine I and generator 6 through aconductor l8 and resistance N. A switch 29 may be interposed between theexcitation system and the field windings 3 and 9. A capacitance 2| isconnected across the terminals of armature windings l of theself-excited generator 6 to consume a leading quadrature current fromthe generator 6, thereby establishing in the generator 6 a magnetomotiveforce which tends to assist the field magnetomotive force provided byfield winding 9.

To control the voltage of the synchronous generator 8 and hence tocontrol the energization of the field winding 3 of dynamo-electricmachine i in accordance with a predetermined controlling infiuence ofthe machine I, such as the armature current thereof, I provide avariable impedance inductive device 22 having a core member 22, awinding 23 connected across armature winding l of generator 6 and havingcontrol windings 24 and 25. The control windings 2d and 25 establishopposing magnetomotive forces which act on the core member 22; and thecon- 7 current controlling resistance 2?. The energization of thecontrol Winding 25 is controlled in accordance with a predeterminedelectrical condition, such as the armature current, of machine 1. Asuitable inductive device, such as a current transformer 28 having aprimary winding 29 and a secondary winding 36, supplies a voltage whichvaries in accordance with the armature current of machine i and effectsenergization of control winding 25 through a unidirectional conductingdevice 3! and an adjustable current controlling resistance 32. Aresistance 29 may be connected across the primary winding of currenttransformer 29 to limit the voltage impressed thereacross.

The operation of the system diagrammatically shown in Fig. 1 will beexplained when the dynamo-electric machine I is operating as asynchronous generator to transmit energy to the alternating currentcircuit 5 and when the excitation system including the self-excitedsynchronous generator 53 is operating to control the energization offield winding 3 of machine I in accordance with a predeterminedcondition such as the armature current of machine 1 to maintain thearmature voltage thereof substantially constant. As will be Wellunderstood by those skilled in the art, direct current will be suppliedto primary winding 3 of machine l and field Winding 5 of generator 6from armature winding 1 of generator 3 through the electric valve meansIt. The capacitance 2i will absorb a leading quadrature current from thearmature winding l of machine 6 to provide a magnetomotive force tendingto assist that furnished by field winding 9. The capacitance 2| alsoserves to initiate the build-up of the excitation of the generator 6. Itis understood that the leading quadrature :current absorbed by thecapacitance 2! establishes a magnetomotive force tending to assist thatdue to field winding 9, and during the initiating stage of the buildingup of the excitation of generator 6 the residual magnetism of the fieldstructure of generator '6 and the assisting action of capacitance 2!will increase the armature voltage to a value sufficient to initiatedischarges within the electric valve means It to supply direct currentto field winding 9 of generator 8 and to field winding 3 ofdynamoelectric machine I. It is also to be noted that the laggingquadrature current consumed by the variable inductive device 22 tends toestablish a magnetomotive force opposing that due to the field winding 9of generator 6, but during the starting operation when the armaturevoltage of the generator 6 is small the energization of control Winding24 will be correspondingly small so that the lagging quadrature currentconsumed by winding 23 will not be appreciable.

The energization of the field winding 3 of dynamo-electric machine I andhence the armature voltage of machine 1 will be controlled in accordancewith the energy transmitted to the alternating current circuit 5 by themachine l. The variable impedance inductive device 22 will absorbvariable amounts of lagging quadrature current from the armature winding7 of synchronous generator 6 to control the armature voltage thereof inaccordance with the current transmitted by the dynamo-electric machine Ito circuit 5. Resistance 2'! is adjusted so that the eifect of controlwinding 25 is normally predominating to cause saturation of core member22' and resistance 32 is adjusted so that control winding 25 furnishesan opposing magnetomotive force of somewhat lesser value than thatprovided by control winding 25. Let it be assumed that the excitationsystem is arranged to maintain the armature voltage of thedynamoelectric machine I at a substantially constant value andfurthermore let it be assumed that the load or armature current of themachine i temporarily increases. As a result of this increase inarmature current, the voltage supplied by the current transformer 28will also increase to effect an increase in the energization of controlwinding 25, thereby decreasing the degree of saturation of the coremember 22 of the inductive device 22. Under this condition, winding 23will absorb a smaller amount of lagging quadrature current from thearmature winding l of generator Gand the armature voltage of generator 6will be increased. Due to this increase in armature voltage there willbe effected an increase in the value of the direct current supplied tofield winding 3 of dynamo-electric machine 1 by electric valve means ittending to restore the armature voltage of dynamoelectric machine i tothe predetermined value. On the other hand, if the load or armaturecurrent of dynamo-electric machine I decreases to a value below apredetermined value or below a predetermined range of values, theenergization of control winding 25 will be decreased to efiect anincrease in the saturation or magnetization of the core member 22' ofinductive device 2! to cause winding 23 to absorb a larger amount oflagging quadrature current from armature winding l of generator 6. ihisincrease in lagging quadrature current will effect a reduction in thearmature voltage of generator 6 and will thereby reduce the voltageimpressed on electric valve means If] to decreasethe excitation ofdynamo-electric machine I to restore the armature terminal voltagethereof to the predetermined value to be maintained.

The variable impedance inductive device 22 not only effects control ofthe armature voltage of the generator 6 to control the excitation of thefield winding 3 of dynamo-electric machine I, but this variableimpedance device also responds in a manner to prevent hunting of thesystem and to stabilize the regulation thereof. More specifically, sincethe variable impedance inductive device 22 is operated within thesaturated region of the magnetic core structure 22, the compensatingvoltage variations of the generator 6 are maintained within apredetermined range of variations during the regulating operation. Thechanges in energization of the control windings 24 and 25 will noteffect proportionate changes in the armature voltage of the generator 6due to the saturation effects of the variable impedance device 22. Whilethe device 22 is effective to maintain the voltage of thedynamo-electric machine l within a predetermined range of values or at apredetermined value under varying load conditions, the regulating actionis stabilized to prevent hunting of the armature voltage of the machineI. The auxiliary or neutral point anode I2 of electric valve means Illalso serves as a stabilizing means for the excitation system undervarying load conditions.

In Fig. 2 of the accompanying drawing there is diagrammatically shown anembodiment of my invention for controlling the conductivities of thedischarge paths of electric valve means ill in order to stabilizefurther the action of the variable impedance inductive device 2'2. Theconductivities of the associated discharge paths are controlled by meansof control members 33 and 34 on which are impressed variable voltages toefiect the stabilizing action. In order to impress on the controlmembers 33 and 34 an alternating voltage controllable in accordance witha predetermined electrical condition such as the voltage of the armaturewinding 1 of generator 6, I provide a stabilizing circuit 35. Thecircuit 35 includes a saturable inductive device or transformer 36having a primary winding 31, a secondary winding 38 with an electricallyintermediate connection 39 and a control winding 40 to control themagnetization or saturation of the core structure thereof. A variableinductance 4| and a variable resistance 42 may be connected in seriesrelation with primary winding 31 of transformer 36 to control the phaseof the alternating voltage impressed on primary winding 31. It will beunderstood by those skilled in the art that I may employ any well knownphase shifting arrangement, either manually operated or automaticallyoperated, to control the phase of the alternating voltage impressed onthe primary winding 31 of transformer 33 to efiect control of theenergization of the field winding 3 of machine I under varying loadconditions. An impedance element, such as a resistance 43, is connectedin circuit with secondary winding 38 and the control memhere 33 and 34of electric valve means It]. More particularly, the resistance 43 isconnected between cathode l3 and the connection 39 of winding 38. As ameans for controlling the energization of the control winding 40 oftransformer 36 and as a means for supplying to resistance 43 a variableunidirectional current, I provide a transformer 44 and a unidirectionalconducting device 45. A current controlling resistance 45 may beconnected in series relation with a secondary winding of transformer 44and unidirectional means I ll.

conducting device 45. The unidirectional conducting device 45 isarranged so that the voltage appearing across resistance 43 tends toimpress on control members 33 and 34 of electric valve means II] anegative unidirectional biasing potential to assist in the control ofthe conductivity of the associated discharge paths.

The operation of the stabilizing circuit 35 shown in Fig. 2 will beexplained by considering the system of Fig. 1 when the arrangementthereof is operating to control the voltage of the dynamoelectricmachine I under variable load conditions. The alternating voltageimpressed on control members 33 and 34 of electric valve means It) isadjusted in phase by inductance 4| and resistance 42 so that therequisite amount of direct current is supplied to field winding 3 fromarmature winding 1 of generator 6 through electric valve Upon increaseof the armature current of dynamo-electric machine I, as explainedabove, the excitation system will respond to increase the Value ofdirect current supplied to the field winding 3. The stabilizingarrangement of Fig. 2 will respond to prevent over-shooting or, in otherwords, to stabilize the regulating action of the variable impedanceinductive device 22 of Fig. 1. When the impedance of winding 23 ofinductive device 22 is decreased under these conditions, the voltageimpressed on anodes H and i2 through conductors l4 and I5 will of courseincrease to efiect an increase in the value of direct currenttransmitted to the field winding 3. By virtue of this increase inarmature voltage of generator 6, the energization of control winding 48of transformer 36 will be increased to effect a retardation in phase ofthe alternating voltage supplied by secondary winding 38. Furthermore,there will be an increase in the value of the unidirectional currentsupplied to the resistance 43 by transformer 44 and unidirectionalconducting device 45 to increase the value of the negativeunidirectional biasing potential impressed on control members 33 and 34.These two effects, acting simultaneously or concurrently, retard thevoltage impressed on control members 33 and 34 relative to the armaturevoltages impressed on anodes H and I2 to decrease temporarily theconductivities of the associated arc discharge paths to limit the valueof the direct current transmitted to field winding 3 of machine I. Inthis way the circuit 35 stabilizes the regulation of the excitationsystem. Of course, it is to be understood that when the load or armaturecurrent of dynamo-electric machine 1 decreases, the excitation systemand the stabilizing circuit will respond to prevent the voltage of thedynamo-electric machine I from swinging below the predetermined value ofarmature voltage of the machine to be maintained.

While I have shown and described my inven tion as applied to aparticular system of connections and as embodying various devicesdiagrammatically shown, it will be obvious to those skilled in the artthat changes and modifications may be made without departing from myinvention, and I, therefore, aim in the appended claims to cover allsuch changes and modifications as fall within the true spirit and scopeof my invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. In combination, an alternating current circuit, a direct currentcircuit, apparatus for interconnecting aid first mentioned circuitscomprising electric valve means having a discharge path i'a'nd a controlmember for controlling the conductivity i thereof, "an excitationcircuitforenergizin'g said control member including a" source 'of alternatingvoltage and 'means for producing a. control voltage "variable in phasean imped- "ance element connected incircuit with said control member forimpressing thereon a biaspotential, and *means comprising a rectifierfor controlling the'phase' of said control voltage -and the magnitude ofsaid bia potential .in accordance -'with an electrical condition of saidalternating current circuit.

: 2. In combination, anialternating current-circuit, 'a'directcurrentcircuit, apparatus for interconnecting said first mentioned circuitscomprising electric valve means having-a discharge path-and a controlmember for controlling the conductivity thereof, and an excitationcircuit includinga saturable transformer having aprimary windingenergized from said alternating 'tialjinaccordance with the voltageofsaid-alternating current circuit.

3. In combination, an alternating current circuit, a-direct currentcircuit, electric translating apparatus connected between said circuitsand 1 comprising an electric valve means having a control member forcontrolling the conductivity thereof, a control circuit for energizingsaid control member comprising phase shifting means including asaturable inductive device 'for controlling the phase ot-the'voltageimpressed upon said azcarso controlmember with respect to the voltage ofsaid alternating current circuit, and means including a unidirectionalconducting device responsive to the voltage-of said alternating current:circuit f'or concurrently controlling said saturable inductive deviceand for impressing 0n said-control member a unidirectionalbiasing po-:tential.

4.1m combination, an-alternating current circuit, a direct currentcircuit, electric translating apparatusconnected between said circuitsand" :device fofiimpressing on said control member an alternatingvoltage variable in phase with re- -.spect:t o the voltage of saidalternating current circuit and including a control winding, and meansfor variably energizing said control winding and .forimpressingonsaid-control member a unidirectional .biasing potential variable inaccordance with the voltage of said alternating current :circuit.

"5. In v combination,. an alternating current circuit,:.a.directicurrent circuit, electric translating apparatus connectedbetween said circuits and comprising electric valve means having acontrol member for controlling the conductivity thereof, an excitationcircuit comprising phase shifting .means including a saturable inductivedevice I for impressing .on said control member a voltage variable inphase vwith respect to .the voltage of said alternating currentcircuit,.and 'a;stabilizing circuit comprising means including aunidirectional conducting device for simultaneously-controllingsaidsairurable inductive device and for impressing von said controlmember a variable negative unidirectional biasing poten- 'tial.

RICHARD TRC'JGER.

